在为iOS5编译FFMPEG时遇到大问题

Question

I'm trying to compile the ffmpeg library for iOS5. I tried different options but none works.

I downloaded this: https://github.com/ciphor/ffmpeg4ios .

I tried the original build_armv7 but it didn't work. I edited the build_arm7 file and now it looks like this:

#!/bin/tcsh -f

if (! -d armv7) mkdir armv7
if (! -d lib) mkdir lib

rm armv7/*.a

make clean

./configure --disable-network --disable-mpegaudio-hp --disable-lpc --disable-vaapi 
--disable-vdpau --disable-hwaccels --disable-mmx --disable-mmx2 --disable-sse 
--disable-ssse3 --disable-avx --disable-amd3dnow --disable-amd3dnowext --disable-vis 
--disable-mmi --disable-doc --disable-yasm --disable-ffmpeg --disable-ffplay 
--disable-ffprobe --disable-ffserver --disable-rdft --disable-dxva2 --disable-encoders 
--disable-decoders --enable-decoder=h264 --disable-bsfs --disable-protocols 
--disable-indevs --disable-outdevs --disable-devices --disable-filters --disable-demuxers --enable-demuxer=h264 
--disable-muxers --disable-parsers --enable-parser=h264 --enable-cross-compile --arch=arm 
--target-os=darwin 
--cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-llvm-gcc-4.2 --as='gas-preprocessor/gas-preprocessor.pl /Aplications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-llvm-gcc-4.2' 
--sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk --cpu=cortex-a8 
--extra-cflags='-pipe -Os -gdwarf-2 -issysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk -m${thumb_opt:-no-thumb} 
-mthumb-interwork' --extra-ldflags='-arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk' --enable-pic


make

mv libavcodec/libavcodec.a armv7/
mv libavdevice/libavdevice.a armv7/
mv libavformat/libavformat.a armv7/
mv libavutil/libavutil.a armv7/
mv libswscale/libswscale.a armv7/

rm lib/*.a

cp armv7/*.a lib/

But i get this error:

/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-llvm-gcc-4.2 is unable to create an executable file. C compiler test failed.

I looked all over the Internet. I have read all the posts on stackoverflow about this but none helped me. Please tell me what i'm doing wrong and please don't post me links: trust me, i saw them all!

Answer 1

That worked for me with iOS 5.0 and Snow Leopard. You have to change ldflags, sysroot and cc to provide valid paths to files in Mountain Lion for Xcode was moved to antoher folder.

./configure \
--extra-ldflags=-L/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.0.sdk/usr/lib/system \
    --disable-muxers \
    --disable-demuxers \
    --disable-devices \
    --disable-parsers \
    --disable-protocols \
    --disable-filters \
    --disable-bsfs \
    --disable-doc \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-avfilter \
    --disable-avformat \
    --disable-ffserver \
    --disable-decoders \
    --disable-encoders \
    --disable-network \
    --enable-decoder=h261 \
    --enable-decoder=h263 \
    --enable-decoder=h263p \
    --enable-encoder=h261 \
    --enable-encoder=h263 \
    --enable-encoder=h263p \
    --enable-cross-compile \
    --enable-hardcoded-tables \
    --enable-memalign-hack \
    --enable-neon \
    --arch=arm \
    --target-os=darwin \
    --cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc \
    --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.0.sdk \
    --cpu=cortex-a8 \
    --extra-cflags='-arch armv7 -mno-thumb -mfpu=neon -mfloat-abi=softfp' \
    --extra-ldflags='-arch armv7 -mno-thumb -mfpu=neon -mfloat-abi=softfp' 2>&1 | tee configure.log

    make clean 
    make

Answer 2

Inspect config.log file in your root compilation directory and search for "C compiler test failed.`' You will find right there the command that was tried and the exact reason why it failed (ie, the compiler output).

It could be that the compiler installation directory is not /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/, or that some library cannot be found, etc...

Actually, what I see is that you are specifying on the configure command line a few paths. Have you checked that they are correct for your Xcode version?

Answer 3

If you require ffmpeg 11 You may need to use snow leopard or lion, Mountain lion seems to be missing critical gcc compiler components. We are looking into fixing our build scripts for this

If version isn't all that important to you, we have a pre-built framework for ffmpeg 8, really we don't find any great difference between using the two and find that ffmpeg 8 has less performance issues.

https://github.com/mooncatventures-group/ffmpegDecoder

If you have a build box with lion or snow leopard you can probably modify our build script and build ffmpeg 11 , others have done this.